title: Claudin-1, -2, -3, -4, -5, and -7 in usual interstitial pneumonia and sarcoidosis.
abstract: The aim of this study was to study the expression of various claudins in sarcoidosis, usual interstitial pneumonia (UIP), and normal human lung. The expression and cell-specific localization of claudin-1, -2, -3, -4, -5, and -7 was analyzed by IHC. Bronchiolar epithelial cells showed mostly strong expression for claudin-1, -2, -3, -4, and -7 and mainly weak expression for claudin-5 in UIP, sarcoidosis, and normal lung. Three claudins, claudin-3, -4, and -7, were expressed in normal alveolar epithelium, mainly in type II pneumocytes. Claudin-5 was expressed strongly in endothelium of normal lung, and its staining was extremely intense in endothelium of UIP. Moderate or strong expression for claudin-1, -2, -3, -4, and -7 was observed in metaplastic alveolar- and bronchiolar-type epithelium in UIP and also in metaplastic alveolar-type epithelium in sarcoidosis. Expression of claudin-5 was mainly weak in metaplastic alveolar- and bronchiolar-type epithelium in UIP. We conclude that claudin-1, -2, -3, -4, -5, and -7 are expressed in UIP and sarcoidosis, and furthermore, the most prominent enhancement of staining is localized in metaplastic alveolar- and bronchiolar-type epithelium in UIP compared with the healthy lung.
authors.affiliation: Institute of Clinical Medicine, Department of Internal Medicine, PO Box 5000, University of Oulu, Fi-90014 Oulu, Finland. Riitta.Kaarteenaho-Wiik@oulu.fi
authors.forename: Riitta
authors.initials: R
authors.lastname: Kaarteenaho-Wiik
authors.forename: Ylermi
authors.initials: Y
authors.lastname: Soini
mesh_terms: D062445:Claudin-1; D062465:Claudin-3; D062506:Claudin-4; D062507:Claudin-5; D057167:Claudins; D006801:Humans; D007150:Immunohistochemistry; D008168:Lung / Q000378:metabolism; D017563:Lung Diseases, Interstitial / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis*; D020545:Respiratory Mucosa / Q000378:metabolism; D017565:Sarcoidosis, Pulmonary / Q000378:metabolism*
chemical_list: C568108:CLDN1 protein, human; C491875:CLDN2 protein, human; C568122:CLDN3 protein, human; C568157:CLDN4 protein, human; C107466:CLDN5 protein, human; C473255:CLDN7 protein, human; D062445:Claudin-1; D062465:Claudin-3; D062506:Claudin-4; D062507:Claudin-5; D057167:Claudins; D008565:Membrane Proteins